Drivers Feel Pinch at Pump

American consumers, already struggling to adjust to higher taxes, now face another challenge: gasoline prices that have risen nearly 50 cents a gallon in the past month alone.

The national average price for regular gasoline hit $3.78 a gallon on Thursday, up 15 cents in the past week and 47 cents in the past month, according to auto club AAA. The increases, driven in part by speculators betting on stronger U.S. gasoline demand, have...